Ashoka adopted Buddhism as his personal faith, which is mentioned in:

On conquering Kalinga the Beloved of the Gods felt remorse, for when an independent country is conquered the slaughter, death and deportation of the people is extremely grievous to the Beloved of the Gods and weighs heavily on his mind. What is even more deplorable to the Beloved of the Gods is that those who dwell there, whether brahmanas, shramanas, or those of other sects, or householders who show obedience to their teachers and behave well and devotedly towards their friends, acquaintances, colleagues, relatives, slaves and servants, all suffer violence, murder and separation from their loved ones. Today if a hundredth or a thousandth part of those people who were killed or died or were deported when Kalinga was annexed were to suffer similarly, it would weigh heavily on the mind of the Beloved of the Gods. The Beloved of the Gods considers victory by dhamma to be the foremost victory.